The most common and severe type is Ducchenne’s muscular dystrophy , which is a X-linked recessive disorder, affecting 1 in 3,500 live male births . DMD children show early symptoms of muscle degeneration, frequently develop contractures, and lose the ability to walk between 6 and 12 years of age.These disorders vary in their age of onset, in severity and in the pattern of which muscles are affected. All forms of muscular dystrophy, however, grow worse as muscles progressively degenerate. In some types of muscular dystrophy, the heart, the gastrointestinal system, endocrine glands, the skin, the eyes and other organs may be affected. MD weakens muscles over time, so children, teens, and adults who have the disease can gradually lose the ability to do things like walking or sitting up.
Diagnosis:
The muscular dystrophy is diagnosed by muscle biopsy, DNA testing, electromyogram (E M G) and nerve conduction velocity (N C V). Blood enzyme tests are helpful because degenerating muscle become "leaky". They leak enzymes, which can then be detected in the blood. Presence of these enzymes in the blood at higher than normal levels is a sign of muscular dystrophy. One such enzyme is Creatine kinase, or CK. The CK level is elevated in many forms of muscular dystrophy, some forms resulting in a higher level than others.Types:
The major forms of muscular dystrophy are myotonic, Duchenne, Becker, limb-girdle, facioscapulo-humeral, congenital, oculo-pharangeal, distal and Emery-Dreifuss. Some of these names are based on the locations of affected muscles. For example, "facioscapulo-humeral" refers to the muscles that move the face, scapula (shoulder blade) and humerus (upper arm bone). Others are based on the type of muscle problem involved ("myotonic" means difficulty relaxing muscles), the age of onset of the disease (as in "congenital," or birth-onset, dystrophy), or the doctors who first described the disease (Duchenne, Becker, Emery and Dreifuss are doctors’ names). Forms of muscular dystrophy differ in severity, age of onset, muscle first and most often affected, the rate at which symptoms progress, and the way the disorders are inherited.Duchenne muscular dystrophy (DMD) is the most common childhood muscular dystrophy and results from mutations in the dystrophin gene. Itis characterized by (i) Onset of muscle weakness usually before 4 years of age, (ii) Selective muscle involvement of pelvic and pectoral girdles, (iii) Hypertrophy of the calves muscle, (iv) grossly elevated serum C K levels and (v) Relentlessly progressive weakness of muscle, leading to inability to work within 10 years of onset and later to contractures and thoracic deformity. There is no specific cure in any system of medicine and the death usually occurs before the age of 20 years caused by respiratory failure or less frequently by cardiac involvement.(4) New and promising experimental strategies to address DMD have been developed over the last few years and some of them are in or are approaching clinical trials. Different therapeutic options are being investigated, ranging from mutation-specific treatments, including nonsense codon suppressors and exon skipping, to gene therapy using viral and nonviral vectors and cell-based approaches.
Becker muscular dystrophy (BMD) was initially described by Becker and Kiener in 1955. The signs, symptoms and the course of Becker muscular dystrophy (BMD) are similar to those of Duchenne but generally appear later and progress more slowly. BMD is generally milder than DMD. The clinical distinction between the 2 conditions is relatively easy because (i) less severe muscle weakness is observed in patients with BMD and (ii) affected maternal uncles with BMD continue to be ambulatory after age 15-20 years. Accuracy of diagnosis has been refined with the recognition of the dystrophin gene defects and with dystrophin staining of muscle biopsy specimens. The progression is typically slower, with the ability to walk usually preserved in to the 30s. The severity of the disease varies, and boys and men with Becker dystrophy have a longer life expectancy than those with Duchenne. The progression of weakness depends on how much dystrophin is made and how well it functions in the muscles.
Limb-girdle muscular dystrophies (L G M D) are neuromuscular disorders characterized by proximal muscular weakness of the pelvic and shoulder girdles and a variable progression with symptoms, ranging from very severe to mild (7), (4). The onset of Limb Girdle Muscular dystrophy (L G M D) is generally in adolescence or early adulthood. In most common forms, L G M D causes progressive weakness that starts in the hips and moves to the shoulders. The weakness progresses to include the arms and legs. Within 20 years of onset, walking is difficult.
TREATMENT OPTIONS
There
is no specific treatment to cure or halt MD. Physical therapy,
exercise, orthopedic appliances (such as braces and wheelchairs), or
corrective orthopedic surgery may help to preserve muscle function and
prevent joint contractures as much as possible and improve quality of
life. Steroids have been used to slow disease progression, but do not
affect the final outcome. Identification of the specific genes
responsible for the various types of MD has led to extensive research on
gene and molecular therapy, but all such treatments are still
experimental.STEM CELL THERAPY FOR MUSCULAR DYSTROPHY
Several different therapeutic options under investigation, including adult-derived stem cell transplantation. Results show that the healthy stem cells provide an effective source of immediately available muscle regenerative cells as well as a reserve pool that can maintain muscle regenerative activity in response to future challenges.http://www.stemcellsmumbai.com/diseases-treated/muscular-dystrophy
No comments:
Post a Comment